Gas sensors such as a non-dispersive infrared (“NDIR”) gas sensor may measure gas concentrations based upon infrared absorption. Specifically, NDIR gas sensors measure the gas concentrations based on unique absorption characteristics specific to each gas at certain wavelengths. In other words, different gases have clearly defined absorption characteristics. The NDIR gas sensors may include an infrared source and an infrared detector. The infrared source may be modulated and the measured signal may be correlated to the gas concentrations. A waveguide may be used as the gas sample chamber between the source and the detector. The internal surface of the waveguide typically is smooth and reflective so as to minimize the scattering of the infrared light therein. The waveguide surface thus may provide near specular reflections so as to maximize the signal received at the detector.
Although the smooth surface providing nearly specular reflections may minimize scattering and maximize the signal, a gas sensor using such a surface also may be sensitive to mechanical changes. For example, temperature changes may have an impact on the components and, hence, the reliability of the signal. As a result, known attempts to increase overall gas sensor stability have involved the use of precision components and/or burn in periods so as to stabilize the electronics therein. These techniques, however, generally may be expensive and/or time consuming.
There is thus a desire for an improved gas sensor such as a NDIR gas sensor. Such an improved NDIR gas sensor may provide overall mechanical stability for a more homogeneous signal without requiring the use of expensive components or modifications.